repairing the front of 86 floor pan. was there sheet metal sandwiched? PICS

repairing the front of 86 floor pan. was there sheet metal sandwiched? PICS

edit** no there wasnt sheet metal oem

the photos below are not for the faint of heart. after spending many hours on the interior of this car, making it look new, I am going to repair the underside of the car.

this thread is dedicated to the repair of the floor pan where a rather large!!! hole in the 45degree angled front wall of the driver side floor pan (like where your pedals press against the floor pan).

I have a question for those of you with knowledge:

you will see in the photos what i found when i pulled off the black tar based covering to what was a completely botched bubba repair.

my question is: was there any metal originally on this forward "wall" of the foot wall? In the repair, there appears to be a piece of metal slid between two 'layers' of smc fiberglass.

that piece of sheet metal completely totally rusted away and was rotting. that was what i could smell and its why i decided to pull it off and re-do it.

i can see the passenger side for an idea of what its supposed to look like on the outside with the X and all, but what i'd like to know is if there was in fact a layer of sheetmetal this far forward in the floor pan. i know about the metal in the rearward portion of the floorpan under the seat mounting locations, but i was under the impression that the rest of the forward section of the floorpan was pure smc.

i am going to have to cut much of this out, to get away from the rust. i will then use sand and wipe with MEK to clean all the rust staining of the SMC and prepare the substrate for good adherence.

I would like to cut it out and rebuild it but im not interested in any metal between smc as it appears to just rust out like crazy!

thnx for guidance and help. VT.

this is the car i paid $650 for and it runs perfectly, but as you can see, when you pay so little for a car, its going to need some "deeper" layers of TLC. This is only ever going to be a driver car, obviously, so the repair needs to be structural and long lasting, not neccessarily returning the panel to look like OEM.

I have considered buying a cut out chunk of panel from a yard but by the time I get it here, it will be 4 weeks from now and cost me $200. I think I can do this for less than that and much quicker to get back out driving. Comments welcome. Cheers.

this smelled like rot is all i can say. i wanted it off. this is the forward wall of the driver side foot well. covered in tar.

that was was under it.

a piece of metal was sandwiched between an outer layer of 'repair' and in front of the outer side of the inner SMC panel. it rusted from the bottom up and had crumbled.

here my finger is on the 'inner' layer of SMC. this i

here my finger is showing how water had collected behind this outer layer of what i assume was smc.

this blob looks like OEM adhesive for the tin heat shield which was disintegrated into rust from the moisture that had been collecting there for years.

Last edited by VikingTrad3r; 09-14-2017 at 12:58 AM.
Reason: no there wasnt sheet metal oem

I also agree with you about the front face of the firewall and the bend at the bottom of it should all be SMC. And if my memory serves me correctly..the firewall caps over the lower floor pan area where it is bonded.

Now GM did glue and rivet on metal caps to the outer face of the lower bend to aid in giving it strength on some models.

Sectioning in a good part from a donor car is quite do-able..and using the correct adhesive made for bonding SMC is good also. But depending on how much overlap you can get when you bond your new panel in place.

If I have any concerns about structural integrity...I would them laminate in some mat and epoxy resin from WEST SYSTEMS ( resin part number 105 and hardener part number 206) to the inside to make sure it is all now one piece...so-to-speak.

Also..depending on the 2 part bonding adhesive you buy....I would HIGHLY advise you to talk the tech line of that company after reading the preparation/application instructions. If the preparation instructions are vague in this area and not clearly written out...HOW you grind the area can make a difference. Some manufacturers want a light scuff for maximum adhesion....while others want a really rough scratch. SO...make sure you how to prep it correctly before you apply it...or it might not bond as it was designed.

I also agree with you about the front face of the firewall and the bend at the bottom of it should all be SMC. And if my memory serves me correctly..the firewall caps over the lower floor pan area where it is bonded.

Now GM did glue and rivet on metal caps to the outer face of the lower bend to aid in giving it strength on some models.

Sectioning in a good part from a donor car is quite do-able..and using the correct adhesive made for bonding SMC is good also. But depending on how much overlap you can get when you bond your new panel in place.

If I have any concerns about structural integrity...I would them laminate in some mat and epoxy resin from WEST SYSTEMS ( resin part number 105 and hardener part number 206) to the inside to make sure it is all now one piece...so-to-speak.

Also..depending on the 2 part bonding adhesive you buy....I would HIGHLY advise you to talk the tech line of that company after reading the preparation/application instructions. If the preparation instructions are vague in this area and not clearly written out...HOW you grind the area can make a difference. Some manufacturers want a light scuff for maximum adhesion....while others want a really rough scratch. SO...make sure you how to prep it correctly before you apply it...or it might not bond as it was designed.

DUB

Thank You for taking the time to reply DUB.

Here is the plan as of now, feedback from any and all welcome:

I have a call into a local boneyard and I am heading over with a cutting wheel to remove an area larger than the size i need to patch on my 86.

I will then remove the driver side interior from my car and will attempt to mark off with a sharpie some sensible cut lines from reference points that i can locate on both pieces of floor pan.

From there, should be a matter of ensuring i have no electrical or brake lines that will get damaged and taking necessary precautions to protect them. I will very likely make the extraction cut from INSIDE my car and very likely i will be dropping the pedals for this. I will tape off the under dash to keep any dust out and use a shop vac to collect dust.

For the replacement, i will fit as best i can, and then on the UNDER side hold it in place using that red 'tuct tape' and carry out the correct bonding from INSIDE. Sag should collect on the tape, which will be removed afterwards and the seam ground out and a fresh underside application made. Then a final grind on the underside.

You mentioned that the heat shield/strength reinforcements along the leading/lower edge of the firewall were both bonded and riveted. Quite correct i think because i did see what looked like rusted cirucular lumps that resembled what was once a rivet. Not sure if there was an overlapping seam between an upper and lower panel somewhere on the front wall, i couldn't make any of it out as it was all gone. I will attempt an overlap on the repair install, even if it is only an inch with a bevelled grind, and i will attempt a rivet on the lower sheet metal shield install.

-------

Product Selection:

I had forgotten that i have used evercoat 100836 professional panel bond 60 before and i checked out the label, and it does say SMC approved.

That said, its old and I will get a new tube of it. I have the gun that is the oddball big/small size. I'll do research and be sure I am getting the correct SMC to SMC bonding material and be sure to reach out and ask for prep instructions, including a query about grinding a bevel to both edges causing an overlap.

Clamping...Not sure how I will clamp the joint! Perhaps this is why the factory used rivets. I'll do the same unless others have a more workable suggestion.

Thanx for all the comments so far! Should have it completed by end of week.

I kinda gave this some thought today at work and what you are thinking sounds good. As long as you clean the SMC well so your red duct tape will stay put...which I know you will test. Nothing is worse that having the panel fall out when you are working on it...and that is coming from my past experiences.

So much of it will depend on how you want it to look from teh underside when done. Some people want it so you can not tell...others do not care as long as it is structurally solid.

Then it will depend if you are going to butt it up to you cut or do an overlap which will cause for both panels to be ground on and tapered so when they are put onto each other...there is little to no raised edge where the ends of the panels end. This can take A LOT of time and precise grinding and fitting...but it can be done. And you would want a good 1 inch+ of an overlap...even if you were to laminate or apply some type of bonding strip on the inside going over the end of the panel. The same holds true if you butt the panels together. And you might also want a bonding strip made out of stainless steel on the underside that will be bonded with the appropriate adhesive and also using pop rivets.

There are many different ways that this can be accomplished and still be structurally solid.

I have been quoted 185$ USD for the driver side foot well/fire wall area. This is me bringing my cut out part into the shop, and them cutting a piece out to match it with a 2" overlap larger from the size of my piece.

Does this sound fair to you guys?

I have SMC approved panel bond on the way.

The price does sound fair to me but i don't have much reference.

This doesn't include the install price, just the extraction price. I'll do the install myself.

If/when you are doing any of the glass cutting/sanding etc, do yourself a favor and where a mask, one that will remove particulates. Since me wife has become a "lung navigator" dealing with patients that show up in the ER room and have lung nodules discovered, I have become more aware and careful. Not all lung nodules are cancer, some are from foreign objects (like fiberglass) being breathed in and lodged, then the body tries to wall them off.

That was a public service message (and reminder) now back to the regularly scheduled forum thread.

When i had this car apart inside (Ive completely rebuilt the interior) I did peel back the dynomatting to see what was there and I couldnt see anything. The reason is because its under the rubber foam backed interior firewall matting. I pulled out the interior tonight to get prepped for cutting and i discovered that there was a fibreglass patch laid down from the interior...up against the metal re-inforcement that had been riveted in. Then from the outside, they put that tar based undercoating as a big patch over the whole operation.

I have to remove that interior foam backed rubber mat up against the firewall.

It looks like it goes up on top of the dash and I recall seeing it up there when i had the dash pad off.

So.....that leaves me with very little choice but to use a utility knife and cleanly cut it out to give me as much room as I need to carry out a professional grade repair. i dont want that rubber mat obscuring the view or workspace.

Once complete, i can use a strip of rubber (think rubber inner tube and weldwood dap contact cement and i can butt the seams i created up against each other with the rubber parch spanning the cut. i cant think of any better way and im open to suggestions.

Once that space is opened up, the repair should be quite straightforward, though im going to go through a crapload of panel bond. I want to be sure it is water tight as well as structural and im going to use a LOT of bonding material along the overlapped seams of both smc pieces. i can alsways grind off the extra bead squigged out.

I have a feeling that this would be a very expensive repair had i taken it into a shop with the labour involved with prep and whatnot. Im feeling lucky to have a shop to carry out the repair in and there is no pressure as its a discretionary hobby car.

Im willing to take the time here because this is a big visible repair and my wife and i or daughters will be in this car for years ro come. Destined for trying an LS swap once we wear out the 130k mile engine.

I ran over a 6 foot long piece of angle iron on the freeway at 70 MPH and it ripped up my footwells. I used fiberglass mat with cardboard underneath to support the repair. In retrospect, I should have used Saran Wrap or similar to allow the support to be removed cleanly. I figured it would never be seen, so I made no attempt to make it pretty:

I used fiberglass mat with cardboard underneath to support the repair. In retrospect, I should have used Saran Wrap or similar to allow the support to be removed cleanly.

Quote:

Release Agent:Any of a number of materials applied to the mold surface before part fabrication, in order to aid in the release of the piece from the mold. These could be waxes, oils or specialty release coatings such as PVA .

The only thing you did wrong was to omit a "release agent". If you had waxed the cardboard with a product, such as Meguiar's Mold Release Wax

i dont know how this happened but one of the reasons corvettes are so great is that the body is *not* metal and there is less to concern yourself with rust.

hopefully these photos will deter others from using steel plates. perhaps when this repair was done a long long time ago, pieces of floor pan were not easily accessible and affordable and perhaps when this repair was first done it was installed correctly....but i doubt it.

Ill pick up my floor pan and see what we can do here for a structural and professional repair to the best of my hobbyist ability!

Honestly....Now seeing it from the inside and the patch removed....I would laminate it up and not use a patch panel. The only way I would use a patch panel is if I has a donor car outside and could cut it out...and I still think I would stop and still prefer to laminate this area up. But that is only because I do a lot of laminating and this area does not intimidate me at all.

Ising the cut out and fraft in method i can use a dremel and get this new panel down so that it should fit like a glove and ill even get the 'X' back.

Im picking up the panel tomorrow.

ive researched and acetone is what is recommended to clean the substrate and then ill sand a feather the edges on the 2" overlap. Bonding with 3' panel bond, and ill use aluminum rivets as well as a bit of clamping force.